Bruce Ely/The OregonianAndre Miller had 27 points and 11 assists against Chicago, whose coach, Tom Thibodeau, called him "one of the best point guards in the league."

To Chicago coach Tom Thibodeau, there was a simple reason his Bulls suffered a 109-103 loss to the Trail Blazers at the Rose Garden on Monday:

Defense -- or rather, poor defense by his players.

“This is two games in a row we put ourselves in bad position because we’re not guarding,” Thibodeau said. “We weren’t able to take anything away from them. It was an easy game for them offensively.”

As an assistant coach, Thibodeau was the architect of Boston’s stellar defense that keyed the Celtics' 2008 NBA title. This season, he built the Bulls’ rise into an Eastern Conference contender around a tough defense that had been ranked No. 1 in opponents’ field goal percentage (.425) and No. 3 in points against (92.1).

After a 101-90 loss at Golden State on Saturday, the Bulls were looking to re-establish a defensive tone against the Blazers. Instead, Portland scored 13.5 points over its season average and shot 51.5 percent from the field.

“You’re playing with fire,” Thibodeau said. “You’re trying to outscore them, and that’s not our game.”

The Bulls had no answer for Blazers forward LaMarcus Aldridge, who torched them for the second time this season. Aldridge had 33 points in the Blazers’ loss at Chicago on Nov. 1, then had a career-high 42 points on Monday.

“Aldridge is tough because of his skill set,” Thibodeau said. “He’s a knock-down shooter from 17, 18 feet. He’s got a terrific post game, he’s got a high release, it’s very difficult to get to his shot.”

Chicago also could not contain Blazers point guard Andre Miller, who had 27 points and 11 assists. Thibodeau, who prepared for Miller many times during Miller’s three seasons with the 76ers, had high praise for the veteran.

“I’ve said this for a long time: I think Andre Miller is one of the best point guards in the league,” Thibodeau said. “He’ll make you pay for every body-position mistake you make. He makes people better, and he made us pay tonight. He got where he wanted with the ball, and he played a great game.”

Chicago (34-16), which still has the third-best record in the Eastern Conference, got its usual superb performance from All-Star point guard Derrick Rose, who had 36 points.

The Bulls were so focused on their poor defense, Thibodeau didn’t object to their huge free throw deficit. The Blazers shot 36 37 for 40 at the line, while Chicago took only 18 free throws and missed seven.

“There wasn’t one aspect of our defense that was good,” he said. “We were slow reacting, and then we did a lot of reaching and gambling. That led to fouls. And then you put them at the line and you gift them points.”